Washington: The leak of classified documents online is a "deliberate criminal act", said the Pentagon press secretary Brigadier. Gen. Patrick Ryder on Thursday as he underlined the US continue to review a variety of factors as it relates to safeguarding classified materials.

During a press briefing on Thursday (local time), Pat Ryder told reporters, "We continue to review a variety of factors as it relates to safeguarding classified materials -- this includes examining and updating distribution lists, assessing how and where intelligence products are shared and a variety of other steps," according to The Hill.

"I would say, though, that it is important to understand that we do have stringent guidelines in place for safeguarding classified and sensitive information. This was a deliberate criminal act, a violation of those guidelines," he added.

Several media outlets reported during the press conference that Massachusetts Air National Guard member Jack Teixeira, 21, had been detained by authorities in connection with the document breach.

In connection with a massive leak of US military intelligence information, the FBI has stated that it has "made an arrest and is continuing to undertake authorised law enforcement action at a property in North Dighton, Massachusetts," according to Al Jazeera.

The jailed individual was identified by attorney general Merrick Garland as 21-year-old Massachusetts Air National Guard member Jack Teixeira.

However, Ryder avoided any comment on details of the report or confirming Teixeira's identity but said that the Pentagon and other agencies are working "around the clock" to understand the scale and scope of the leak.

According to Al Jazeera, leaks of classified US documents have revealed key state secrets, including information about Ukraine's plans for a spring offensive, and raised suspicions that the US has been spying on its allies.

In connection with the Pentagon document leaks, Jack Teixeira's arrest has been announced by US Attorney General Merrick Garland.

"In conjunction with an investigation into the unauthorised removal, retention, and communication of classified national defence material, the Justice Department said today that Jack Douglas Teixeira had been detained. Teixeira works for the Air National Guard of the United States," Al Jazeera reported Garland as saying.